Tenascin C (TNC) is an extracellular matrix glycoprotein up-regulated in solid tumors. Higher TNC expression is shown in invading fronts of breast cancer, which correlates with poorer patient outcome. We examined whether TNC induces epithelial-mesenchymal transition (EMT) in breast cancer. Immunohistochemical analysis of invasive ductal carcinomas showed that TNC deposition was frequent in stroma with scattered cancer cells in peripheral margins of tumors. The addition of TNC to the medium of the MCF-7 breast cancer cells caused EMT-like change and delocalization of E-cadherin and ␤-catenin from cell-cell contact. Although amounts of E-cadherin and ␤-catenin were not changed after EMT in total lysates, they were increased in the Triton X-100-soluble fractions, indicating movement from the membrane into the cytosol. In wound healing assay, cells were scattered from wound edges and showed faster migration after TNC treatment. The EMT phenotype was correlated with SRC activation through phosphorylation at Y418 and phosphorylation of focal adhesion kinase ( Epithelial cells are polarized and tightly interconnected by cellular junctions, whereas mesenchymal cells never form stable intercellular contacts in adult tissues. Epithelial-mesenchymal transition (EMT) is a process whereby polarized epithelial cells are converted into mesenchymal cells during embryogenesis and in diseased tissues. 1-4 EMT events also take place during tumor progression in association with invasion and metastasis, when carcinoma cells stably or transiently lose their epithelial polarity and intercellular connections, allowing them to escape the surrounding epithelium and acquire higher locomotive behavior like mesenchymal cells. 2,[5][6][7][8] Many recent studies have demonstrated that EMT is controlled by complex signaling pathways initiated from tyrosine-receptor kinases, transforming growth factor-␤ (TGF-␤) receptors, Wnt pathways, Notch pathways, and integrins, which are triggered by various extracellular signals. 2,4,9 The activated pathways, including RAS/ mitogen-activated protein kinase, phosphoinositol 3 kinase, SRC, and focal adhesion kinase (FAK), also induce cytoskeletal reorganization, causing dissociation of E-cadherin from the membrane, loss of epithelial morphology, and increased cell motility. 2,4,9,10 Expression of transcriptional regulators such as SNAI1/2 and TWIST, followed by transcriptional switching from epithelial markers to mesenchymal ones, also has been reported. 2,11,12

Tenascin-C (TNC), a large hexameric extracellular glycoprotein, is a pleiotropic molecule with multiple domains binding to a variety of receptors mediating a wide range of cellular functions. We earlier reported that TNC induces epithelial–mesenchymal transition (EMT)-like change in breast cancer cells. In the present study, we clarified TNC receptor involvement in this process. Among integrins previously reported as TNC receptors, substantial expression of αv, α2, β1 and β6 subunits was detected by quantitative PCR and immunoblotting in MCF-7 cells. Integrin β6 mRNA was remarkably upregulated by transforming growth factor (TGF)-β1 treatment, and protein expression was prominently increased by additional exposure to TNC. Immunofluorescent labeling demonstrated integrin αvβ6 accumulation in focal adhesions after TNC treatment, especially in combination with TGF-β1. The α2 and β1 subunits were mainly localized at cell–cell contacts, αv being found near cell cluster surfaces. Immunoprecipitation showed increase in αvβ1 heterodimers, but not α2β1, after TNC treatment. Activated β1 subunits detected by an antibody against the Ca2+-dependent epitope colocalized with αv in focal adhesion complexes, associated with FAK phosphorylation at tyrosine 925. Neutralizing antibodies against αv and β1 blocked EMT-like change caused by TNC alone. In addition, anti-αv and combined treatment with anti-β1 and anti-αvβ6 inhibited TGF-β1/TNC-induced EMT, whereas either of these alone did not. Integrin subunits αv, β1 and β6, but not α2, bound to TNC immobilized on agarose beads in a divalent cation-dependent manner. Treatments with neutralizing antibodies against β1 and αvβ6 reduced αv subunit bound to the beads. Immunohistochemistry of these receptors in human breast cancer tissues demonstrated frequent expression of β6 subunits in cancer cells forming scattered nests localized in TNC-rich stroma. These findings provide direct evidence that binding of αvβ6 and αvβ1 integrins to TNC as their essential ligand induces EMT-like change in breast cancer cells.

The introduction of anti-inflammatory therapies has enabled substantial improvement of disease activity in patients with inflammatory bowel diseases (IBD). However, IBD can lead to serious complications such as intestinal fibrosis and colorectal cancer. Therefore, novel therapies reducing the development of these complications are needed. Angiotensin II (Ang II) promotes tissue inflammation by stimulating the production of monocyte chemoattractant protein-1 (MCP-1) or proinflammatory cytokines. It plays a pivotal role in IBD progression. Although blockade of Ang II has been reported to ameliorate experimental colitis and reduce colorectal cancer risk, the cellular and molecular mechanisms remain poorly understood. Our previous work showed that irbesartan, an Ang II type 1 receptor blocker, reduced the number of C–C chemokine receptor 2-positive (CCR2+) monocytic cells in the inflamed pancreas. This study aimed to investigate the possible antifibrotic and antitumour effects of irbesartan using the azoxymethane/dextran sodium sulphate mouse model. Irbesartan suppressed MCP-1 production and the accumulation of Ly6C+CCR2+ monocytes and fibrocytes in the inflamed colon, downregulated the expression of type 1 collagen and matrix metalloproteinase 9 and inhibited the development of intestinal fibrosis and tumours. Our observations suggest that blocking the MCP-1/CCR2 pathway using irbesartan might be beneficial in preventing colitis-associated colon tumours.

We report a patient who developed persistent PVB19 infection from an RBC transfusion containing low levels of PVB19. This is the second case of transfusion-mediated PVB19 infection since the introduction of CLEIA in 2008. Transmission may occur in immunocompromised patients lacking PVB19-neutralizing antibodies. The report of further such cases will allow the establishment of minimal threshold values and more effective screening tests for PBV19 transmission through RBC products.

We investigated the involvement of CXCL12-CXCR4 interactions in human lymphohematopoiesis by coculture with telomerized human stromal cells. CXCR4 expression was low in CD34CD38CD45RACD10CD7CD19 immature hematopoietic stem/precursor cells (HSPCs) but higher in CD34CD38CD45RACD10CD7CD19 early lymphoid precursors and even higher in CD34CD38CD45RACD10CD7CD19 pro-B cells. Inhibition of the effect of stromal cell-produced CXCL12 by an anti-CXCR4-blocking Ab suppressed the generation of CD45RACD10CD7CD19 early T lymphoid precursors (ETPs) and CD45RACD10CD7CD19 B lymphoid precursors on stromal cells, but it did not affect the generation of ETPs in conditioned medium of stromal cell cultures. Replating assays showed that contact with stromal cells was critical for HSPC-derived CD45RACD10CD7CD19 B lineage-biased precursors to differentiate into CD19 pro-B cells, which was suppressed by the anti-CXCR4 Ab. Conversely, HSPC-derived ETPs possessed T and B lymphoid and monocytic differentiation potential; stromal cell contact was not required for their growth but rather promoted B lymphoid differentiation. The anti-CXCR4 Ab did not affect the growth of ETPs in conditioned medium, but it suppressed their B lymphoid differentiation on stromal cells. CD14CD11cHLA-DRCD123CD303 plasmacytoid dendritic cells developed from HSPCs and ETPs exclusively in contact with stromal cells, which was suppressed by the anti-CXCR4 Ab. These data indicate that CXCL12 plays an essential role in stromal cell contact-mediated B lymphoid and plasmacytoid dendritic cell differentiation from immature hematopoietic and early T lymphoid precursors with a multilineage differentiation potential, but it does not participate in contact-independent generation of early T lymphoid precursors.